1 - Digital Rights Management is a euphemism. It is like saying someone who died has "passed away" or "moved on." It is absolutely not about protecting creator's rights, it's about protecting business profits. Those CAN coincide, but as often as not do NOT. DRM means, to me, needless restrictions placed legitimate customers in a Quixotic attempt to stop "rampant" piracy. Fighting piracy is as simple as Netflix and Steam sales, which is far more effective than having to be logged into a server 24/7 to play. It is all well and good that creators want others to not mess with their work - that isn't what DRM is about, however. It's about power and control, about wanting to make you rebuy games and, if they could help it, pay every time you start to play it (think DivX.)
2 - License keys are a form of DRM, yes. They are minor annoyances, but they are annoyances. I won't bay at the moon over them, I freely accept them as an acceptable compromise - but they are a compromise that is more like an exterior hook and eye lock on a door with a sign saying "Do Not Open Unless You Are The Property Owner" - it's highly ineffectual. Does the actual owner of the house have THAT MUCH an inconvenience to undo that every time he goes inside? No. But that inconvenience really outweighs any level of protection it illusorially provides.
3 - Any attempts on the publisher/seller's end to control how I access the content I bought, adding unnecessary hoops for me to jump through just to try and make sure I really REALLY bought it, are DRM.
4 - Smaller demo. Either give me the game for free, completely, and ask me to pay what I think it is worth, or give me a scaled down demo and ask me to pay when I want to get the full game and then I get the full game. No unlock codes.
5 - Demos are great. I don't personally use demos nearly as much as I should, but I have used them (most recently I can think of are KoA:R and ME3) and think that trying before you buy is the right way to go. I think reviews (and the rest), both "professional" as well as normal gamer ones, are useful but need to be parsed carefully.